Flexible seal assembly

ABSTRACT

Flexible seal assemblies having a relatively low torsional rigidity and high longitudinal flexure to thereby allow the flexible seal assembly to flex between adjacent components and maintain a seal, even when movement between adjacent components occurs, is described. In some embodiments, the flexible seal assembly includes one or more layers of metal matrix material, the metal matrix material being comprised of a plurality of short segments of thin wire arranged randomly and sintered together to form a semi-rigid sheet. The one or more layers of metal matrix material can be sandwiched between an upper casing and a lower casing of a metal alloy casing. In various embodiments, additional features are provided for helping to make sure the seal assembly stays together, such as spot welds formed through the seal assembly, an S-shaped casing, and a recess/protrusion feature provided on adjacent layers of metal matrix material.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. patent application Ser.No. 16/005,044, filed Jun. 11, 2018, which claims priority to U.S.Provisional Application No. 62/518,487, filed Jun. 12, 2017, theentirety of which is hereby incorporated by reference.

TECHNICAL FIELD

The present application relates to flexible seal assemblies, and morespecifically, flexible seal assemblies having a relatively low torsionalrigidity and high longitudinal flexure to thereby allow the flexibleseal assembly to flex between adjacent components and maintain a seal,even when movement between adjacent components occurs.

BACKGROUND

In many industrial applications, such as gas turbines and aerospaceturbines, several components are assembled together in a circular and/orsegmented fashion. These arrangements typically result in the creationof gaps between adjacent segments. Such gaps are generally undesirable,as they create paths for air and gas leaks that, if not filled orclosed, decrease operation efficiency.

Historically, these gaps have been filled using cloth seals or laminateseals. However, both solutions provide limitations in one or more offlexure, durability, sealing, and temperature resistance. For example,problems associated with previously known seals used to fill gapsbetween adjacent components include leakage along the longitudinal axis,lack of durability (e.g., brittleness), increased number of potentialleak paths, wear issues, lack of compliancy, and limited resiliency.

Accordingly, a need exists for improved sealing assemblies that reduceor eliminate some or all of these limitations.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary, and the foregoing Background, is not intendedto identify key aspects or essential steps of the claimed subjectmatter. Moreover, this Summary is not intended for use as an aid indetermining the scope of the claimed subject matter.

Described herein are various embodiments of a flexible seal assemblysuitable for use in applications such as gas turbines or aerospaceturbines where a flat seal between adjacent components is required inorder to improve operating efficiency. In some embodiments, the flexibleseal assembly comprises one or more layers of a metal matrix sheetmaterial, and a metal casing fully or partially encapsulating the one ormore layers of the metal matrix sheet material. The metal matrix sheetmaterial can be made from a plurality of segments of thin wire arrangedin a random fashion to create a sheet structure, and which are thensintered together to form a semi-rigid sheet. The metal casing can bemade of a metal alloy.

This composite structure provides a flexible seal assembly that has arelatively low torsional rigidity and high longitudinal flexure tothereby allow the flexible seal assembly to flex between adjacentcomponents and maintain a seal, even when movement between adjacentcomponents occurs. The low torsional rigidity/high longitudinal flexurealso reduces wear to the components that come into contact with the sealassembly that can be caused by previously known rigid seal assemblies.Additionally, the casing protects the interior metal matrix sheetmaterial to thereby improve the operational lifetime of the sealassembly, but without sacrificing the flexibility of the seal assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the disclosed flexiblesealing assembly, including the preferred embodiment, are described withreference to the following figures, wherein like reference numeralsrefer to like parts throughout the various views, uncles otherwisespecified.

FIGS. 1A and 1B illustrate top, cross-sectional, and side views of twoversions of a multi-layered flexible seal assembly according to variousembodiments described herein;

FIG. 2 illustrates a flexible seal assembly according to embodimentsdescribed herein inserted in a slot provided in a component to be sealedaccording to various embodiments described herein;

FIG. 3 illustrates top, cross-sectional and side views of amulti-layered flexible seal assembly having an S-shaped casing accordingto various embodiments described herein;

FIG. 4 illustrates top, cross-sectional and side views of amulti-layered flexible seal assembly according to various embodimentsdescribed herein; and

FIGS. 5A-5I illustrate top, cross-sectional and side view of variousflexible seal assemblies according to various embodiments describedherein.

DETAILED DESCRIPTION

Embodiments are described herein more fully below with reference to theaccompanying Figures, which form a part hereof and show, by way ofillustration, specific exemplary embodiments. These embodiments aredisclosed in sufficient detail to enable those skilled in the art topractice the invention. However, the embodiments may be implemented inmany different forms and should not be construed as being limited to theembodiments set forth herein. The following Detailed Description is,therefore, not to be taken in a limiting sense.

With reference to FIG. 1A, a flexible seal assembly 100 according tovarious embodiments described herein is illustrated. The flexible sealassembly 100 of FIG. 1A includes three layers of metal matrix sheetmaterial 110 a, 110 b, 110 c stacked one on top of the other andsandwiched between a metal casing 120, which includes an upper metalcasing 120 a and a lower metal casing 120 b. The layers of metal matrixsheet material 110 a, 110 b, 110 c can have the same dimensions andshape such that edges of the layers of metal matrix sheet material 110a, 110 b, 110 c can be aligned when stacked together. The metal casing120 provides a protective barrier on the top and bottom of the threelayers of metal matrix sheet material 110 a, 110 b, 110 c, while theends of the layers of metal matrix sheet material 110 a, 110 b, 110 care left exposed (see, e.g., Detail AD, which is an end view of the sealassembly 100). The sides of the layers of metal matrix sheet material110 a, 110 b, 110 c are also exposed (see, e.g., Detail AD), but theupper metal casing 120 a and the bottom 120 b do each include slantedoverhangs 122 a, 122 b that partially protect the sides of the layers ofmetal matrix sheet material 110 a, 110 b, 110 c.

Each metal matrix sheet material layer 110 a, 110 b, 110 c is generallycomprised of multiple segments of thin wire arranged at random andsintered together to form a semi-rigid sheet material. The material ofthe thin wire used to create the shorter segments can generally be anysuitable type of metal material and will typically have a diameter ofless than 0.010 inches. The thin wire is cut into short segments, suchas segments having an aspect ratio of around 20. For example, when thediameter of the thin wire is 0.010 inches, the length of the individualsegments cut from the wire is typically in the range of 0.200 inches.

The thickness of a layer of the metal matrix sheet material is generallynot limited, and may be as thin as approximately the two times thediameter of the wire segments used. The thickness of the metal matrixsheet material can be increased by using more segments piled on top ofeach other when the segments are randomly arranged to form the sheetstructure.

The randomly arranged segments are sintered in order to bond togethersegments that contact one another. Sintering is generally carried out byusing a heat-treating process. Any temperature can be used for thesintering step provided that the temperature is sufficient to bondtogether the metal segments without destroying the structural integrityof the wires. Similarly, the sintering can be carried out for any periodof time provided that the bonding together of metal segments occurs.Other processing steps can also be used in the creation of the sheets,such as additional sintering steps and/or calendaring steps. Suchadditional processing steps can be used to achieve, for example, desireddensity, tensile strength, thickness and permeability.

The overall dimensions (x, y and z directions) of the metal matrix sheetmaterial are generally not limited and may be selected based on thespecific application in which the seal assembly will be used. In someembodiments, 3 feet by 3 feet sheets of metal matrix sheet material areprepared (with any suitable thickness), and smaller sections are cutfrom the larger sheets in order to provide the layers of metal matrixsheet material used in the seal assembly.

The upper casing 120 a and the lower casing 120 b of the casing 120 aregenerally formed of any suitable metal alloy. Metal alloys are suitablefor use because they do not overly restrict the flexibility of the sealassembly while still providing sufficient protection to the metal matrixmaterial layers 110 a, 110 b, 110 c. As discussed above, the sealingassembly 100 shown in FIG. 1A provides an upper protective barrier and alower protective barrier for the upper and lower surfaces of the stackof metal matrix material layers 110 a, 110 b, 110 c. The ends of thestack may be exposed while the sides are partially exposed. As shown inFIG. 1A, the sides of the upper and lower casings 120 a, 120 b mayinclude inwardly slanted overhangs 122 a, 122 b to partially protect thesides of the metal matrix material layers. The angle of these slantedoverhangs 122 a, 122 b is generally not limited, and may be from about5° (i.e., practically parallel with the rest of the casing 120) to about90° (i.e., at a right angle to the rest of the casing 120). In someembodiments, the slanted overhangs 122 a, 122 b are at an about 45°angle.

In some embodiments, the casings 120 a and 120 b are attached to themetal matrix material sheets 110 a, 110 b, 110 c in order to create thefinal seal assembly 110 and keep the separate metal matrix materialsheet layers of the seal assembly 100 together. Any manner of attachingthe metal matrix material sheet layers can be used. In some embodiments,the attachment is via a mechanical fastening mechanism, such as a clipor vice. In some embodiments, the attachment is via a welding, fusion,brazing or sintering process. As shown in FIG. 1A, a series of spotwelds 130 are used in order to attach together the upper casing 120 a,the metal matrix material layers 110 a, 110 b, 110 c and the lowercasing 120 b.

The sealing assembly 100 shown in FIG. 1B is similar to the sealingassembly 100 shown in FIG. 1A, save for the use of only two metal matrixmaterial layers 110 a, 110 b. While FIGS. 1A and 1B show three layer andtwo layer structures, respectively, any number of metal matrix materiallayers can be used including one layer or more than three layers.

FIG. 2 illustrates the manner in which a seal assembly as describedherein may be used in conjunction with components requiring sealingtherebetween. A component of a turbine 200 is shown including a slot201. The seal assembly 100 from, for example, FIG. 1A or 1B, can beinserted into the slot 201. A second component (not shown) to bepositioned adjacent component 200 includes a similar slot that receivesthe other side of the seal assembly 100. In this manner, the sealassembly 100 blocks any gap that might exist or be formed between theadjacent components, which consequently improves operating performanceof the, for example, turbine. The seal assembly 100 has a low torsionalrigidity and high flexibility, and can therefore accommodate anymovement of the components while still maintaining an effective seal andwithout damaging the components.

With reference to FIG. 3 , an alternate embodiment of a seal assembly300 is shown wherein the casing 310 is in the form of an S-shape suchthat an intermediate metal layer 310 a is provided between the layers ofmetal matrix material 320 a, 320 b. The material of the metal matrixmaterial layers 320 a, 320 b and the casing 310 can be similar oridentical to the material described above with respect to metal matrixmaterial layers 110 a, 110 b, 110 c, and casing 120.

Each metal matrix material layer 320 a, 320 b is provided within eitherthe top or bottom portion of the S-shaped casing 310 and is retainedwithin the casing 310 by angled end portions 311 of the S-shaped casing310. In such an embodiment, there may be no requirement for additionalsecurement means, as the assembly stays together by virtue of the metalmatrix material layers 320 a, 320 b being tucked within the upper andlower portion of the S-shaped casing 310 and the angled portion 311maintaining the metal matrix material layers 320 a, 320 b within theupper and lower portions of the S-shaped casing.

While not required based on the self-retaining configuration of theembodiment shown in FIG. 3 , the seal assembly 300 can further includemeans for attaching together the metal matrix layers 320 a, 320 b andthe casing 310, such as via a mechanical fastening mechanism (e.g., aclip or vice), welding, fusion, brazing or sintering process.

With reference to FIG. 4 , another alternate embodiment of a sealingassembly 400 is shown wherein the metal matrix material layers 420 a and420 are formed with a protrusion and recess, respectively, to helpmechanically link the two layers together. The material of the metalmatrix material layers 420 a, 420 b and the casing 410 can be similar oridentical to the material described above with respect to metal matrixmaterial layers 120 a, 120 b, 120 c, and casing 110.

In the embodiment shown in FIG. 4 , metal matrix material layer 420 aincludes a protrusion 420 a-1, which can be made of locally accumulatedsegments of thin wire sintered together. Similarly, metal matrixmaterial layer 420 b includes a recess 420 b-1 that is arranged andsized to receive the protrusion 420 a-1 and thereby mechanicallymaintain the two layers together in at least a longitudinal direction.In other words, the protrusion 420 a-1 and recess 420 b-1 can preventlongitudinal sliding of the two layers away from each other. The sealassembly 400 also includes an upper casing 410 a and lower casing 410 b.

While not required based on the self-retaining configuration of theembodiment shown in FIG. 4 , the seal assembly 400 can further includemeans for attaching together the metal matrix layers 420 a, 420 b andthe casing 410, such as via a mechanical fastening mechanism (e.g., aclip or vice), welding, fusion, brazing or sintering process.

FIG. 5A illustrates another embodiment of a seal assembly wherein themetal matrix material layer 510 is a single layer. Additionally, theupper metal casing 520 a and the lower metal casing 520 b of the metalcasing 520 includes slanted overhangs 522 a, 522 b as in FIGS. 1A and1B, but the metal matrix material layer 510 contacts the slantedoverhangs 522 a, 522 b such that the metal matrix material layer 510extends to the ends of the slanted overhangs 522 a, 522 b, rather thanproviding a gap between the slanted overhangs as in FIGS. 1A and 1B.

The seal assemblies shown in FIGS. 5B-5I have a similar configuration toFIG. 5A, but further include a series of slits 501 formed through theseal assembly. As described in greater detail below, the slits 501 canbe vertical or angled, and can have various sizes, shapes andgeometries. The various slits 501 are provided to alter the rigidity ofthe sealing assembly and allow for more flexibility and torsionalmovement such that the seal assembly is able to move with the componentswith which the seal assembly is used.

FIG. 5B shows several rows of a series of straight line slits 501aligned in a direction parallel with the longitudinal axis of the sealassembly. The slits 501 extend vertically into the seal assembly.

FIG. 5C shows a single continuous wave-like slit 501 formed across thelength of the seal assembly. The slit 501 extends vertically into theseal assembly.

FIG. 5D is similar to FIG. 5C, but the single continuous wave-like slit501 is formed at an angle into the seal assembly.

FIG. 5E shows a series of S-shaped slits 501 formed across the length ofthe seal assembly. The slits 501 extend vertically into the sealassembly.

FIG. 5F shoes a single continuous right-angle wave-like slit formedacross the length of the seal assembly. The slit 501 extends verticallyinto the seal assembly.

FIG. 5G is similar to FIG. 5F, but the single continuous right-anglewave-like slit 501 is formed at an angle into the seal assembly.

FIG. 5H shows a series of slits 501 formed in a direction perpendicularto the longitudinal axis of the seal assembly and extending towards thecenter of the seal assembly from both sides of the seal assembly. Eachslit 501 extending from one side of the seal assembly is aligned with acorresponding slit 501 extending from the opposite side of the sealassembly. Aligned slits 501 extending from opposite sides seal assemblydo not contact each other or overlap.

FIG. 5I shows a series of slits 501 formed in a direction perpendicularto the longitudinal axis of the seal assembly and extending towards thecenter of the seal assembly form both sides of the seal assembly. Eachslit 501 extending from one side of the seal assembly is offset fromslits 501 extending from the opposite side of the seal assembly. Theslits 501 extending from opposite sides of the seal assembly overlap butdo not contact each other.

While shown separately from the seal assembly embodiments of FIGS. 1-4 ,any of the slits configurations shown in FIGS. 5B-5I can be used inconjunction with any of the seal assembly embodiments shown in FIGS. 1-4.

From the foregoing, it will be appreciated that specific embodiments ofthe invention have been described herein for purposes of illustration,but that various modifications may be made without deviating from thescope of the invention. Accordingly, the invention is not limited exceptas by the appended claims.

Although the technology has been described in language that is specificto certain structures and materials, it is to be understood that theinvention defined in the appended claims is not necessarily limited tothe specific structures and materials described. Rather, the specificaspects are described as forms of implementing the claimed invention.Because many embodiments of the invention can be practiced withoutdeparting from the spirit and scope of the invention, the inventionresides in the claims hereinafter appended.

Unless otherwise indicated, all numbers or expressions, such as thoseexpressing dimensions, physical characteristics, etc., used in thespecification (other than the claims) are understood as modified in allinstances by the term “approximately”. At the very least, and not as anattempt to limit the application of the doctrine of equivalents to theclaims, each numerical parameter recited in the specification or claimswhich is modified by the term “approximately” should at least beconstrued in light of the number of recited significant digits and byapplying rounding techniques. Moreover, all ranges disclosed herein areto be understood to encompass and provide support for claims that reciteany and all sub-ranges or any and all individual values subsumedtherein. For example, a stated range of 1 to 10 should be considered toinclude and provide support for claims that recite any and allsub-ranges or individual values that are between and/or inclusive of theminimum value of 1 and the maximum value of 10; that is, all sub-rangesbeginning with a minimum value of 1 or more or ending with a maximumvalue of 10 or less (e.g., 5.5 to 10, 2.34 to 3.56, and so forth) or anyvalues from 1 to 10 (e.g., 3, 5.8, 9.9994, and so forth).

We claim:
 1. A flexible seal assembly comprising: an S-shaped casingcomprising: an upper casing segment; a middle casing segment; and alower casing segment; a first layer of metal matrix material disposedbetween the upper casing segment and the middle casing segment; and asecond layer of metal matrix material disposed between the middle casingsegment and the lower casing segment.
 2. The flexible seal assembly ofclaim 1, wherein the first layer of metal matrix material and the secondlayer of metal matrix material each comprise a plurality of wiresegments randomly oriented and sintered together to form the layer ofmetal matrix material.
 3. The flexible seal assembly of claim 2, whereinthe aspect ratio of each of the plurality of wire segments is about 20.4. The flexible seal assembly of claim 3, wherein the diameter of eachof the plurality of wire segments is less than 0.010 inches.
 5. Theflexible seal assembly of claim 2, wherein the S-shaped casing comprisesa metal alloy.
 6. The flexible seal assembly of claim 2, wherein: an endof the upper casing segment includes a slanted end; an end of the lowercasing segment includes a slanted end; and the slanted end of the uppercasing segment and the lower casing segment are angled towards themiddle casing segment.
 7. A flexible seal assembly comprising: a casingcomprising: an upper casing segment having a first end and a second endopposed to the first end; a middle casing segment having a first end anda second end opposed to the first end; and a lower casing segment havinga first end and a second end opposed to the first end, wherein thesecond end of the upper casing segment is coupled to the second end ofthe middle casing segment and the first end of the middle casing segmentis coupled to the first end of the lower casing segment, and wherein thefirst end of the upper casing segment is angled and the second end ofthe lower casing segment is angled; a first layer of metal matrixmaterial disposed between the upper casing segment and the middle casingsegment; and a second layer of metal matrix material disposed betweenthe middle casing segment and the lower casing segment.
 8. The flexibleseal assembly of claim 7, wherein the first layer of metal matrixmaterial and the second layer of metal matrix material each comprise aplurality of Response to Restriction Requirement dated Nov. 10, 2022wire segments randomly oriented and sintered together to form the layerof metal matrix material.
 9. The flexible seal assembly of claim 8,wherein the aspect ratio of each of the plurality of wire segments isabout
 20. 10. The flexible seal assembly of claim 9, wherein thediameter of each of the plurality of wire segments is less than 0.010inches.
 11. The flexible seal assembly of claim 7, wherein the casingcomprises a metal alloy.